Date: Sat, 17 Oct 1998 14:51:01 +1000 From: Bruce Evans <bde@zeta.org.au> To: mike@smith.net.au, shimon@simon-shapiro.org Cc: freebsd-current@FreeBSD.ORG, jkh@time.cdrom.com Subject: Re: Show Stopper? Failure to Install 19981014 Message-ID: <199810170451.OAA00376@godzilla.zeta.org.au>
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>It appears to be caused by not entering the root filesystem first.
>There's a test in the disklabel code which checks to see if the
>partition you have open to write the label starts at 0, and if not then
>it defaults to the 'a' partition.
Labels should always be written using the RAW_PART partition ('c' on
i386's). If not, then they must be written using a partition that has
offset 0. If not even that, then the 'a' partition must have offset 0.
Unfortunately, newfs(8) writes labels to the same partition that it
is newfs'ing.
>Partitions are laid on disk in the order that you enter them. The 'a'
>partition is always reserved for the partition you mount on /. If you
It's not reserved. It's just the default.
>don't enter this partition first, it won't be at the beginning of the
>disk, and any attempt to rewrite the disklabel will fail.
>
>Due to the way that sysinstall interacts with libdisk, this is
>difficult to get "right". We probably need a bandaid which insists
>that if you want to create an 'a' partition you must lay it down first.
This is easy to fix by changing the (whole) test in writedisklabel() to
`lp->p_partitions[RAW_PART] == 0'. Even that is probably only necessary
to give the right errno (this condition is enforced in several places).
This might wake bugs in other code where partition 0 is magic.
Bruce
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